The contractor will synthesize by the solid-phase method, unlabeled arginine vasotocin, as well as three different radiolabeled arginine vasotocin molecules; i.e., 14C in the tyrosine residue, 3H in the tyrosine residue, and 14 C in the glycine residue. The contractor will also synthesize by classical methods the C-terminal tri-through octopeptides of arginine vasotocin. These compounds will be purified and characterized and delivered to the Laboratory of Biomedical Sciences, NICHD.